1. Technical Field
The present invention is related to positioning of microcomponents, and more particularly to a system and method for fixing the position of a microcomponent such that it is precisely aligned with a target position.
2. Background
Extraordinary advances are being made in micromechanical devices and microelectronic devices. Further, advances are being made in MicroElectroMechanical (xe2x80x9cMEMxe2x80x9d) devices, which comprise integrated micromechanical and microelectronic devices. The term xe2x80x9cmicrocomponentxe2x80x9d will be used herein generically to encompass microelectronic components, micromechanical components, as well as MEMs components. The advances in microcomponent technology have resulted in an increasing number of microcomponent applications. Accordingly, a need often arises for precise positioning of microcomponent devices. For example, it is often desirable to position a microcomponent in alignment with a target position. For instance, for certain applications it may be desirable to align a microcomponent with another device. Because of the small size of microcomponents, they often require very precise positioning (e.g., precise alignment with another device). For example, in some cases a misalignment of only a few microns may be unacceptable. In fact, in some cases the size of the microcomponent being aligned may be only a few microns. Also, microcomponents present particular difficulty in handling and positioning operations.
Microcomponents are commonly implemented in the field of optoelectronics. Generally, when coupling optoelectronic components, alignment is very important. That is, alignment of optoelectronic components is often critical for proper operation of an optoelectronic device. A relatively slight misalignment of optical components may drastically alter an optical device""s performance. For example, accurate alignment of components is often important for ensuring proper propagation of an optical signal to/from/within an optoelectronic device. For instance, optoelectronic modules, such as optoelectronic receivers and optoelectronic transmitters commonly require proper alignment of microcomponents therein for proper operation. In general, proper alignment is desired to minimize the amount of attenuation within such optoelectronic devices.
One microcomponent that often requires proper alignment is an optical fiber. For example, in an optoelectronic receiver, a fiber is aligned with an optical detector, typically a PIN photodiode. Very large fibers may have light-guiding cores with a diameter of approximately 1 millimeter (mm) or 1000 microns (xcexcm), but such fibers are rarely used in communications. Standard glass communication fibers have cladding diameter of 125 xcexcm and light-guiding cores with diameter of approximately 8 to 62.6 xcexcm. Proper alignment of the end of the optical fiber (which may be referred to as the xe2x80x9cfiber pigtailxe2x80x9d) with the optical detector is important to ensure that a light signal is properly received by the optical detector. Similarly, in an optoelectronic transmitter, an optical fiber is aligned with a light source, such as a light-emitting diode (LED) or laser diode. Proper alignment of the end of the optical fiber with the light source is important to ensure that a light signal is properly communicated from the light source to the optical fiber.
The difficulty in achieving proper alignment of optical fiber is often increased because of variances in the size of fiber core diameters. For example, typical commercial graded-index fiber commonly specify a 50 xcexcm nominal fiber core diameter that may vary within a tolerance of xc2x13 xcexcm. Also, alignment/positioning of the light-guiding core within the sleeve of a fiber optic cable often varies (i.e., the core is not always centered within the sleeve), thereby further increasing the difficulty of properly designing a fiber with another optoelectronic device.
Various techniques have been developed for handling and positioning microcomponents, such as optical fibers. According to one technique, a high-precision, external robot is utilized to align microcomponents within devices. However, such external robots are generally very expensive. Additionally, external robots typically perform microcomponent alignment in a serial manner, thereby increasing the amount of time required for manufacturing microcomponent devices. That is, such robots typically perform alignment for one component at a time, thereby requiring a serial process for assembling microcomponents utilizing such a robot.
According to another technique, microactuators, such as electrothermal actuators, may be utilized to align microcomponents, such as optical fibers. For example, microactuators may be integrated within a device to align microcomponents within the device. Accordingly, use of such microactuators may avoid the cost of the above-described external robot. Also, if implemented within a device, the microactuators may enable parallel alignment of microcomponents. That is, multiple devices may have alignment operations performed by their respective microactuators in parallel, which may reduce the amount of time required in manufacturing the devices. Examples of techniques using microactuators integrated within a device to perform alignment of an optical fiber are disclosed in U.S. Pat. Nos. 6,164,837 and 5,602,955.
Once a desired position is obtained for a microcomponent (e.g., alignment with another device) using either of the above techniques, such microcomponent may have its position fixed in some manner such that it maintains the desired position. Various techniques have been developed for fixing the position of microcomponents. According to one technique, an epoxy may be used to fix the position of a microcomponent. In another technique a low melting point bonding material, such as solder, may be used to fix the position of a microcomponent. Exemplary techniques that use solder to fix the position of an optical fiber are disclosed in U.S. Pat. No. 6,164,837, U.S. Pat. No. 5,692,086, and U.S. Pat. No. 5,745,624.
According to another technique, an xe2x80x9cactivexe2x80x9d alignment device may be utilized to fix the position of a microcomponent. Such an alignment device is xe2x80x9cactivexe2x80x9d in the sense that electrical power has to be maintained in order to fix the alignment of a microcomponent. For example, in certain implementations that use microactuators integrated within a device to perform alignment of microcomponents, power to such microactuators must be maintained in order to maintain (or fix) the position of the microcomponents being aligned.
In view of the above, traditional techniques for positioning microcomponents are problematic. First, as described above, high-precision external robots may be utilized for accurately positioning microcomponents, but such robots are very expensive and do not enable parallel manufacturing of devices. Microcomponent devices have been developed in the prior art for positioning microcomponents, which are generally less expensive than the external robots and may enable parallel manufacturing of devices (e.g., may be integrated within devices to perform microcomponent positioning in their respective devices in parallel). Many such microcomponent positioning devices are active in the sense that require continuous power in order to maintain a desired positioning of a microcomponent. Such an active device is generally undesirable. For example, it is generally undesirable to require that power be maintained for positioning a microcomponent within a device that is deployed in the field. Other techniques require use of epoxy or solder to fix the position of a microcomponent. The use of such epoxy or solder increases the complexity of the fixing process, delays the manufacturing time, and may result in inaccurate positioning (because of shifting in the curing/cooling period). Also, certain bonding techniques (e.g., using certain epoxies) may not maintain a microcomponent""s position over a wide range of environmental conditions (e.g., may fail when exposed to very high and/or cold temperatures, as may be experienced by devices deployed in the field). Thus, a method and system are desired that enable accurate positioning of a microcomponent without requiring that power be maintained for maintaining such positioning and without requiring use of epoxy/solder for fixing the microcomponent""s position.
The present invention is directed to a system and method that enable precise positioning of microcomponents. According to one embodiment, a system and method for positioning a microcomponent are disclosed, wherein a microcomponent is received into a microcomponent positioning device. A target position for the microcomponent may then be determined, and at least a portion of the microcomponent positioning device is controllably deformed to accurately fix, at least temporarily, the position of the microcomponent at the target position.
In certain embodiments, at least a portion of the microcomponent positioning device is controllably deformed by heating such portion to a sufficiently high temperature to make it amenable to alteration of its shape. Such heating may comprise electrothermal heating or laser heating, as examples. For instance, according to one implementation, one or more microactuators may be included within the microcomponent positioning device and may be operable to move the microcomponent to various positions. For example, in one implementation microactuators are arranged to enable movement of the microcomponent along two orthogonal axes, and in another implementation microactuators are arranged to enable movement of the microcomponent along three orthogonal axes. In one embodiment, such microactuators may be utilized to first determine a desired target position for a microcomponent, and thereafter, the microactuators may be controllably deformed to fix, at least temporarily, the position of the microcomponent to the target position. For instance, such microactuators may be electrothermally deformed to accurately fix, at least temporarily, the position of the microcomponent to the target position.
In another embodiment, support beams are included for supporting a microcomponent holder, which holds the microcomponent to be positioned. In such embodiment, the support beams may be controllably deformed to fix, at least temporarily, the position of the microcomponent to the target position. For example, the support beams may be heated (e.g., electrothermally heated) to a sufficient temperature such that they become amenable to alteration of their shape, and microactuators may be used to move the microcomponent holder in a manner to determine a desired target position for the microcomponent being held by such microcomponent holder. Once the target position is determined, the microactuators may apply a force to maintain the microcomponent at such target position, and the support beams may be allowed to cool/harden. Thereafter, the microactuators may be deactivated (powered-off), and the deformed support beams maintain the microcomponent holder such that the microcomponent is at the target position.
Accordingly, embodiments of the present invention provide a system and method for accurately positioning microcomponents. Further, according to embodiments of the present invention, the position of a microcomponent may be fixed, at least temporarily, to a target position without requiring power for fixing such position. Additionally, according to embodiments of the present invention, the position of a microcomponent may be fixed, at least temporarily, to a target position without requiring use of epoxy or solder for fixing such position.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention.